The invention relates to a device for axially displacing a shaft in a vehicle transmission, in particular a vehicle transmission of a commercial vehicle.
The present disclosure concerns a device for generating a force parallel to a shaft arranged inside a transmission, and transmitting the generated force to the shaft. The shaft can, for example, be a synchronizer shaft which can be arranged in a vehicle transmission and must be displaced parallel to its axis on operation of the transmission. Because of the necessary bearing and lubrication of the synchronizer shaft and the restricted installation space, a direct connection of the synchronizer shaft to a piston displacing the shaft in the axial direction is not possible since then the necessary piston stroke could not be achieved.
The present invention is based on the object of providing a device which can generate the forces necessary for operation of the transmission on the shaft in the axial direction without direct connection to the shaft.
This and other objects are achieved in accordance with the invention by providing a device for axially displacing a shaft in a vehicle transmission, in particular a vehicle transmission of a commercial vehicle, in which forces are exerted on the shaft of the vehicle transmission in an axial direction via a fork. The device comprises a piston movable in the axial direction in a piston housing, wherein the piston is mounted on an inner guide and wherein an end of the inner guide protrudes from the piston housing on one side and is there connected to and fixed in relation to the housing of the vehicle transmission. Via the fork, the piston can be connected with the shaft in a simple manner, wherein using this construction an arbitrary piston stroke can be achieved because of the axial offset between the shaft and the piston. In order to absorb the transverse forces, which are transmitted via the fork because of the axial offset, perpendicular to the axial direction on the piston, the inner guide is provided, which on one side can protrude beyond the piston housing and there be connected with the transmission housing in order to divert the transverse forces.
Here it can be provided that the piston divides a pressure chamber provided in the interior of the piston housing into a first region and a second region. This allows a pressure-induced shift of the piston in the positive and negative axial direction, wherein both a positive and a negative force can be exerted on the shaft in the axial direction by the two separated regions.
It can furthermore be provided that on the inner guide a groove ring is provided to seal the pressure chamber. This allows separation of any abrasion occurring due to the piston movement from the interior of the transmission.
It can also be provided that a further end of the inner guide protrudes beyond the piston housing on a further side of the piston housing and that a support is provided which receives the further end and fixes this in relation to the housing of the vehicle transmission. By means of this support the flexion of the inner guide under transverse load is reduced, whereby a simpler fixing of the inner guide is possible on the opposite side. This leads to a reduction in component cost.
It can furthermore be provided that the support has a bearing play in a radial direction.
In particular it can be provided that the inner guide has a step against the support. In this way axial forces acting on the inner guide can be diverted to the housing of the transmission.
It can also be provided that the inner guide is designed as a central guide. In this way forces acting on the contact points between the piston and piston housing can be evenly distributed.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of one or more preferred embodiments when considered in conjunction with the accompanying drawings.